ATEX Gear Pumps: II 1/2G Ex h IIB T4 Ga/Gb in Plain Words

Pump Notes · engineering notes from Vimpo Pump

Our ATEX gear pumps carry this marking: II 1/2G Ex h IIB T4 Ga/Gb. Each field has one meaning.

The zones

• Zone 0: an explosive gas atmosphere is present continuously or for long periods, for example inside a tank.
• Zone 1: an explosive gas atmosphere is likely in normal operation.
• Zone 2: an explosive gas atmosphere is not likely, and if it occurs, only for a short time.

The marking, field by field

• II — equipment for surface industries, not for mines.
• 1/2G — category 1 inside the pump and category 2 outside, for gas. The pump is approved for zones 0 and 1.
• Ex h — protection for non-electrical equipment (EN ISO 80079-36/-37).
• IIB — the gas group.
• T4 — the temperature class: the maximum surface temperature is 135 °C. For this reason the liquid temperature is limited to 130 °C.
• Ga/Gb — equipment protection levels for zone 0 and zone 1.

The basis is the EU-type examination certificate IEP 24 ATEX 1315X Suppl. 01, notified body 2284, to Directive 2014/34/EU.

What changes in an ATEX pump

• The seal is always a mechanical seal (MS). Gland packing is not used.
• The motor is of Ex d or Ex e type to EN 60079-0/-1/-7.
• Each temperature or pressure sensor on the pump must itself be Ex protected (zone 1, IIB, minimum T4).
• The maximum differential pressure is lower on some sizes: for example 10 bar on VD-25, 12 bar on VD-40, and 14 bar on VD-50, VD-80 and VD-150.
• In the model code, EX comes after the sealing field and before the drive.

Tell us the zone, the gas group and the liquid temperature. We check the pump, the motor and the sensors against the certificate.

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